LA Respiratory Issues
Endoscopy can be performed standing or in the moving horse. Standing examinations are much easier to perform; however, abnormalities seen on standing examinations may disappear during exercise while different lesions appear. In general practice, the primary goal is generally to determine if advanced diagnostics are indicated and provide options to the client.
Anatomy and physics of the upper respiratory tract- narrated powerpoint
These videos give you a bit of an overview on normal endoscopy
Upper Airway Conditions affecting the Equine Athlete, VCNA: Equine Practice, August 2018, Vol.34(2), pp.427-441